California Department of Transportation traffic cameras showed snow on the ground in the Sierra Nevada on Tuesday morning. San Francisco Bay area commuters, meanwhile, were encountering rain showers.

The National Weather Service has issued a winter storm warning for the central and southern Sierra, where some areas could see as much as a foot of snow. A winter weather advisory was in effect further north. Snow resorts around Lake Tahoe could get up to 8 inches of snow.

The cold system from the Gulf of Alaska is also expected to drop snow at much lower elevations before moving out by Wednesday.